Shutoff devices for flexible delivery tubes



P. T. PUL.MAN 3,38 ,336

SHUTOFF DEVICES FOR FLEXIBLE DELIVERY TUBES May 21, 1968 Filed March 6,1963 FIGJ United States Patent 3,384,336 SHUTOFF DEVICES FOR FLEXIBLEDELIVERY TUBES Prockter Thomas Pulman, Norfolk, England, assignor toThis invention relates to shutoff devices for use with flexible deliverytubes and is concerned with facilitating the mass production of suchdevices.

According to the invention a shutoff device for use with a flexibledelivery tube includes opposed anvil and preloaded spring surfacesbetween which the tube can be disposed, said surf-aces being arrangedfor relative displacement, in response to limited displacement of anoperating member, between a neutral position in which a free flow cantake place through the tube and a shutoff position in which the tube issqueezed between the surfaces under a reactive force exerted by saidpreloaded spring surface. By employing spring loading to squeeze thetube rather than direct pressure from a lever or the like, it ispossible to ensure that the crushing load on the tube is kept with-indesired limits irrespective of manufacturing inaccuracies and tolerancesin the size of tube to be controlled as well as in the parts of thedevice.

In order that the invention may be clearly understood and readilycarried into effect, two embodiments thereof Will now be described indetail with reference to the accompanying drawing in Which FIGURE 1 is asectional elevation showing one form of shutoff device constructed inaccordance with the invention and,

FIGURE 2 is a view similar to FIGURE 1 but showing an alternative formof the device.

Referring now to the drawing, a shutoff device of the inventionincorporates a closed box-like outer casing 1 which is intended formounting in an upright position and has a supply opening 2 in the upperwall which is extended through an externally screw-threaded boss 3. Thisboss 3 then serves to connect the opening 2 with a supply line, notshown. Similarly, an opening is formed in the lower wall through which aconnector 4 for a delivery line is conveniently arranged to extend. Thesupply opening 2 and the delivery connector 4 are connected within thebox by a length of flexible tube 5. Alternatively, of course, theflexible tube length 5 could form part of a continuous feed line whichis passed through the openings in the top and bottom of the box, orcould form part of a flexible supply or delivery line which is continuedinto the box. Extending lengthwise behind the flexible tube length 5within the box is an anvil surface 6 which may be provided by suitablyshaping the back wall 1a of the box.

Also extending lengthwise of the tube length within the box, so as tolie in front of the tube length and opposite the anvil surface 6, is thecross-member 7 of a T-shaped operating member or lever having a stem 8.This lever is fulcrumed at 9 within the box at the junction of thecross-member 7 and stem 8, and the stem is arranged to project through aslot 10 in the front wall 1b of the box. The length of the slot in thefront Wall of the box is such that the lever stem 8 is permitted onlylimited angular movement from a centre or neutral position as shown,before being stopped against one or the other of the ends of the slot10.

Carried on the front face of the cross-member 7 which is directedtowards the flexible tube length 5 is a preloaded leaf spring 11. Thisleaf spring is conveniently in the form of an elongated strip having acentre seating 3,3843% Patented May 21, 1968 which bears on the lever atthe fulcrum, the arms of the leaf spring on each side of the seatingbeing then arranged to diverge rearwardly away from the levercross-member 7 and being returned at their extremities. To load the leafspring, the arms thereof are then pressed further apart and the returnedends are retained under the opposite extremities of the levercross-member 7.

With the arrangement described, a free flow of liquid or particulatematerial can take place through the flexible tube length 5 lying betweenthe anvil and the preloaded spring surfaces, when the device is in aneutral position, -i.e. when the lever stem 8 projects approximatelycent-rally from the slot as shown. A through connection can thus beprovided between supply and delivery lines connecting respectively withthe top and bottom of the casing 1. If, however, the stem 8 is movedtowards one or other of the slot ends, then the flexible tube length 5is progressively squeezed off. Thus, for example, if the lever stem 8 ismoved downwardly towards the bottom of the slot, the lower arm of thelever cross-member, together with the over-lying preloaded springsurface thereon, is moved towards the anvil surface and commences tosqueeze the tube between the two surfaces. By the time the lever stemhas reached its limiting position at the bottom of the slot 10, thelower arm of the cross-member will have moved slightly away from thereturned lower end of the leaf spring 11 and the flexible tube will besqueezed against the anvil surface 6 under the reactive force exerted bythe leaf spring. Exactly the same shutoff procedure will take place ifthe lever stem is moved towards the upper end of the slot 10, the upperarm of the cross-member and the upper part of the preloaded leaf springthen becoming operative.

The projecting lever stem 8 as described is normally intended to supporta load and, to this end, may be provided with an adjustable rider 12 forload suspension. To counterbalance the load, a coil spring 13 isconveniently provided between the front wall 1b of the easing and theupper cross-member arm so that, when the load is equal to the forceexerted by the coil spring, the lever stem is maintained in its neutralposition with the flexible pipe length open to permit free flowtherethrough. If then the load increases or decreases, the lever isangularly displaced in the appropriate direction to shut off theflexible pipe length. In the event that the load increases excessively,however, it will be observed that this will not result in theapplication of an undue crushing force against the flexible tube length,since such force will be limited to the reactive force exerted by theoperative end of the leaf spring. Equally, if the flexible tube lengthhas been made oversize, as a result of manufacturing inaccuracy, thecrushing force thereon is automatically maintained within permittedlimits without individual adjustment.

In the alternative embodiment of the invention illustrated in FIGURE 2,parts which are similar to those in the embodiment of FIGURE 1 are giventhe same reference numerals. In this further embodiment, the boxlikeouter casing 1 has a modified flat back wall 10, the anvil surface beingprovided by the modified cross-member 7a of a T-shaped fulcrumed leverwhich again has a stem 8 and a fulcrum 9. The preloaded spring surfaceis then disposed behind the flexible tube length 5 against the back ofthe casing. Such spring-loaded spring surface may, for example, beprovided as illustrated by the ends of a spring loop 14 the centre partof which seats against the back Wall 1c of the casing whilst the endsare returned over the centre part and tensioned to underlie a stop bar15 disposed between the casing side walls behind the tube length 5 andopposite the lever fulcrum 9. If then the T-shaped operating lever isrocked in one direction or the other, one arm of the crossmember 7a willpress against the flexible tube length which, in turn, will be squeezedagainst a returned end of the loop spring 14 so that the latter willmove away from the stop bar 15. The flexible tube length 5 is then againsubjected to the reassertive force of a preloaded spring surface whichpresses the tube against the anvil surface provided by the associatedcross-member of the operating lever.

In the foregoing, two typical embodiments of the invention have beendescribed and illustrated, but it will be appreciated that variousalternative arrangements for squeezing a flexible tube length betweenthe anvil and a spring surface may also be employed.

To vary the closing pressures exerted by the device of the invention inany of the described embodiments, springs of different characteristicsmay be employed.

I claim:

1. A shutoff device for use with a flexible delivery tube, said devicecomprising a box-like outer casing having a back wall forming an anvilsurface disposed on one side of said tube, a preloaded spring surfacedisposed in facing relationship with said anvil surface on the oppositeside of said tube, means for relatively displacing said surfaces betweena neutral position in which free flow can take place through said tube,and a shutoff position in which said tube is squeezed under a reactiveforce exerted by said preloaded spring surface, and an operating memberfor effecting relative displacement of said surfaces, said operatingmember being in the form of a fulcrumed lever which is arranged fordisplacement about the fulcrum in one direction by an applied load andin the opposite direction by counterbalancing means, said operatinglever being T-shaped and being fulcrumed at the head end Within saidbox-like outer casing, said operating lever having a stem partprojecting between upper and lower stops to support the load, thepermitted angular displacement of said lever about its fulcrum beinglimited by said stops, said preloaded spring surface being associatedwith each arm of the lever cross member, said spring surfaces beingarranged to cooperate alternatively with said anvil surface dependingupon the direction of angular displacement of said operating lever andsaid flexible tube being extended lengthwise of the cross member at thehead end of the lever and between the said cross member and said backwall of the casing to connect supply and delivery openings providedrespectively in the top and bottom of the casing.

2. A shutoff device as claimed in claim 1 in which said spring surfacesare provided by a tens ioned leaf spring having a centre seating on thecentre of the lever cross-member and arms on each side of the seatingwhich diverge rearwardly away from the cross-member and have returnedends which are retained behind the opposite arms of the cross-member,the said spring arms being operable alternatively to squeeze theflexible tube depending upon the direction of angular displacement ofthe lever.

References Cited UNITED STATES PATENTS 682,279 9/1901 Bade 251-7 X1,190,039 7/1916 Tatum 251-10 1,432,882 10/1922 Lobl M 251-6 2,872,0782/ 1959 Kennedy 25 l-7 X 3,054,425 9/1962 Pribonic 25l9 X 2,010,2298/1935 Goff et al 25l9 XR 2,895,653 7/1959 Giepen 25l9 XR 3,105,74510/1963 Vieli 25l9 XR FOREIGN PATENTS 83,421 10/ 1895 Germany. 103,9302/1917 Great Britain. 462,057 3/1937 Great Britain.

WILLIAM F. ODEA, Primary Examiner. R. GERARD, Assistant Examiner.

1. A SHUTOFF DEVICE FOR USE WITH A FLEXIBLE DELIVERY TUBE, SAID DEVICECOMPRISING A BOX-LIKE OUTER CASING HAVING A BACK WALL FORMING AN ANVILSURFACE DISPOSED ON ONE SIDE OF SAID TUBE, A PRELOADED SPRING SURFACEDISPOSED IN FACING RELATIONSHIP WITH SAID ANVIL SURFACE ON THE OPPOSITESIDE OF SAID TUBE, MEANS FOR RELATIVELY DISPLACING SAID SURFACE BETWEENA NEUTRAL POSITION IN WHICH FREE FLOW CAN TAKE PLACE THROUGH SAID TUBE,AND A SHUTOFF POSITION IN WHICH SAID TUBE IS SQUEEZED UNDER A REACTIVEFORCE EXERTED BY SAID PRELOADED SPRING SURFACE, AND AN OPERATING MEMBERFOR EFFECTING RELATIVE DISPLACEMENT OF SAID SURFACES, SAID OPERATINGMEMBER BEING IN THE FORM OF A FULCRUMED LEVER WHICH IS ARRANGED FORDISPLACEMENT ABOUT THE FULCRUM IN ONE DIRECTION BY AN APPLIED LOAD ANDIN THE OPPOSITE DIRECTION BY COUNTERBALANCING MEANS, SAID OPERATINGLEVER BEING T-SHAPED AND BEING FULCRUMED AT THE HEAD END WITHIN SAIDBOX-LIKE OUTER CASING, SAID OPERATING LEVER HAVING A STEM PARTPROJECTING BETWEEN UPPER AND LOWER STOPS TO SUPPORT THE LOAD, THEPERMITTED ANGULAR DISPLACEMENT OF SAID LEVER ABOUT ITS FULCRUM BEINGLIMITED BY SAID STOPS, SAID PRELOADED SPRING SURFACE BEING ASSOCIATEDWITH EACH ARM OF THE LEVER CROSS